Keyboards are used on many handheld devices, including telephones and mobile communication devices. The size of keyboards has been reduced over the years, as newer, smaller devices have become popular. Cell phones, for example, are now sized to fit in one's pocket or the palm of the hand. As the size of the devices has decreased, the more important it has become to utilize all of the keyboard surface as efficiently as possible.
Many keyboards on mobile devices have an input device for navigation through the graphical user interface, for example, a device, such as a trackball or rotating wheel, that operates to move a cursor or pointer or scrolls up and down a page. This navigation device often occupies a relatively large amount of space on the mobile device, because it is repeatedly used, and finer control is sometimes required to accomplish navigation than to simply press a key. To accommodate a larger, more convenient navigation device on the housing of a mobile device, the amount of space that is available for the keys of the keyboard or other input devices must be reduced. Therefore, a user must sacrifice larger keys for a conveniently sized navigation device, or vice-versa.
Another keyboard spacing problem is that of finger overlap when keys are smaller than the user's finger and are spaced closely together. Because keys near the center of the keyboard are surrounded by other keys, they are particularly more difficult to press without the user's finger overlapping and inadvertently pressing an adjacent key.